Using screens safely at night

Using screens at night adversely affects sleep, but there are some things you can do to help protect your eyes.

Click here to read about a new study, published in PNAS, that measures the sleep impact of reading an iPad before bed.

Adjusting your screen

  • Learn how to adjust your device’s brightness, and dim it as far as possible at night.
  • Use f.lux at 2300K or below to remove the alerting blue light from screens. If you prefer using f.lux at higher color temperature settings, you should dim your screen as well. Currently on iOS, we are only able to offer f.lux on jailbroken devices.
  • Most phones and tablets can invert colors, displaying white text on a black background. If you use a backlit device to read at night, learn how to change this setting. It’s a good way to reduce the light coming from your phone.
  • We do not recommend the use of software that claims to reduce blue light by adding a red overlay to your screen. This reduces contrast, and requires even more brightness for readability. Instead, dim as far as you can.
  • If you’re using a desktop or laptop, your screen is likely larger and more alerting than an iPad. If you can’t install f.lux or dim your screen, try to plan your computer time earlier in the day so you can spend a couple hours winding down before bed.
  • How close you hold your device affects brightness. A screen held 6 inches away exposes you to about 4 times more alerting light as one held 12 inches away - and that’s still too close.

Adjusting your habits

  • Surprisingly short exposures of bright light can have alerting effects, so avoid bright light for an hour or two before bed.
  • This also means: no peeking at your phone when you should be sleeping.
  • Set your circadian clock by seeing some natural light each day. Even sitting near a window or being outdoors on a cloudy day is usually brighter than daytime artificial lighting indoors.
  • Orange glasses can be used to block alerting light. However, “blue-blocking” coatings and lenses that look yellow are designed to block UV and this will not help with circadian timing. You’ll know it’s the right color if you put them on and say, “Wow, that’s too orange.”
  • Bright lighting in your house also alerts your body. Use dimmers if you have them, or turn off brighter lights before bed.
  • Dimming your lights actually helps twice, because it will make you more comfortable dimming your screen.
  • If you have kids: Children require more sleep and are significantly more sensitive to blue light than adults, so these effects may be significantly greater for younger eyes.

21 Dec 2014

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